Drill-Down DataGrid with Nested DataGrids

I am trying to create a datagrid that dynamically populates it cells with nested datagrids. The solution works on the idea that clicking on the select column of the master datagrid will dynamically insert the child data into another datagrid within one of the selected rows cells. This works fine when drilling down one layer. I need the select button on the nested grid to create another grid within its own grid. However, when I click on the nested select button the whole master datagrid collapses. It seems that I need to be able to keep the master grid expanded on postback. I am fairly new to .Net so I'm not sure that what I am attempting is even possible. Any help or better alternatives will be greatfully received.

Here is the code:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.IO;

namespace YVPersonnel
{

      public class uiCompanyMaintenence3 : System.Web.UI.Page
      {
            protected System.Web.UI.WebControls.DataGrid dgDivision;
            protected System.Web.UI.WebControls.DataGrid dgSite;
            
            private static string cns = "Data Source=localhost;Initial Catalog=YVPersonnel;Integrated Security=SSPI";
            private SqlConnection cn = new SqlConnection(cns);

            protected System.Web.UI.WebControls.TextBox TextBox1;
            protected System.Web.UI.WebControls.TextBox TextBox2;
            
            public int divisionID;
            public int siteID;


            private void Page_Load(object sender, System.EventArgs e)
            {
                  dgDivision.SelectedIndex = Convert.ToInt32(Cache["divisionIndex"]);

                  if(!Page.IsPostBack)
                  {
                        getDivisionDataSet();
                  }
            }

            private void getDivisionDataSet()
            {
                  beDivision oDivision;
                  
                  oDivision = new beDivision();

                  dgDivision.DataSource = oDivision.getDivisionDataSet(cn);

                  dgDivision.DataBind();
            }

            private DataGrid createSiteDataGrid(int divisionID)
            {            
                  SqlCommand cmd = new SqlCommand("select * from yvsite where divisionid = " + divisionID, cn);

                  DataGrid dgSite = new DataGrid();

                  dgSite.AutoGenerateColumns = false;
                  
                  SqlDataAdapter da = new SqlDataAdapter(cmd);

                  DataSet ds = new DataSet();

                  cn.Open();

                  da.Fill(ds);

                  dgSite.DataSource = ds;

                  EditCommandColumn Edit = new EditCommandColumn();
                  Edit.EditText = "Edit";

                  TemplateColumn Select = new TemplateColumn();
                  Select.ItemTemplate = new DataGridTemplate(ListItemType.SelectedItem, "Select");

                  BoundColumn SiteID = new BoundColumn();
                  SiteID.HeaderText = "SiteID";
                  SiteID.DataField = "siteid";

                  BoundColumn Site = new BoundColumn();
                  Site.HeaderText = "Site";
                  Site.DataField = "shortName";

                  TemplateColumn newDG = new TemplateColumn();
                  
                  dgSite.Columns.AddAt(0, Select);
                  dgSite.Columns.AddAt(1, SiteID);
                  dgSite.Columns.AddAt(2, Site);
                  dgSite.Columns.AddAt(3, newDG);
                  dgSite.Columns.AddAt(4, Edit);
                  dgSite.Columns[1].Visible = false;

                  dgSite.DataBind();
                        
                  cn.Close();

                  dgSite.SelectedIndexChanged += new System.EventHandler(dgSite_SelectedIndexChanged);
                  
                  return dgSite;
            }

            
            #region Web Form Designer generated code
            override protected void OnInit(EventArgs e)
            {
                  //
                  // CODEGEN: This call is required by the ASP.NET Web Form Designer.
                  //
                  InitializeComponent();
                  base.OnInit(e);
            }
            
            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {    
                  this.dgDivision.SelectedIndexChanged += new System.EventHandler(this.dgDivision_SelectedIndexChanged);
                  this.Load += new System.EventHandler(this.Page_Load);

            }
            #endregion


            private void dgDivision_SelectedIndexChanged(object sender, System.EventArgs e)
            {
                  divisionID = Convert.ToInt32(dgDivision.SelectedItem.Cells[1].Text);

                  DataGrid dgSite = createSiteDataGrid(divisionID);

                  dgDivision.SelectedItem.Cells[3].Controls.AddAt(0, dgSite);

                  if(dgDivision.SelectedIndex > 3)
                  {
                        dgDivision.Enabled = false;
                        dgSite_SelectedIndexChanged(this.dgSite, e);
                  }
            }


            private void dgSite_SelectedIndexChanged(object sender, System.EventArgs e)
            {
                  TextBox1.Text = "Bugger!";      
            }      
      }
}



Cheers!